1. Field of the Invention
This invention relates to catalyst system for the polymerization of olefins, particularly, to a catalyst system comprising a supported Ziegler-Natta catalyst. The catalyst system is used to polymerize olefins, such as ethylene.
2. Description of the Prior Art
Polyolefin manufacturing processes typically involve the polymerization of olefin monomer with a Ziegler-Natta type catalyst. Catalyst systems for the polymerization of olefins are well known in the art. Typically, these systems include a Ziegler-Natta type polymerization catalyst component and a co-catalyst, usually an organoaluminum compound. Examples of such catalyst systems are shown in the following U.S. Pat. Nos. 3,574,138; 4,316,966; and 5,173,465, the disclosures of which are hereby incorporated by reference.
A Ziegler-Natta type polymerization catalyst is basically a complex derived from a halide of a transition metal, for example, titanium or vanadium, with a metal hydride and/or a metal alkyl, typically an organoaluminum compound, as a co-catalyst. The catalyst is usually comprised of a titanium halide supported on a magnesium compound complexed with an alkylaluminum co-catalyst.